Switch with over-travel actuator



A ril 15, 1969 A. J. CARLI 3,439,134

SWITCH WITH OVER-TRAVEL ACTUATOR Filed March 28, 1966 fi l6 GEQTU IINVENTOR.

ALVIN J. CARL) WW VII-f" United States Patent 3,439,134 SWITCH WITHOVER-TRAVEL ACTUATOR Alvin J. Carli, Sebring, Ohio, assignor toConsolidated Electronics Industries Corp., a corporation of DelawareFiled Mar. 28, 1966, Ser. No. 538,051 Int. Cl. H01h 3/16 US. Cl. 20047 3Claims ABSTRACT OF THE DISCLOSURE A switch is disclosed which is simpleand reliable and constructed of few parts. A lever is moved in a firstdirection and stresses a wire-like spring which in turn has anotherportion deflecting a leaf spring carrying a switch contact. Considerableover-travel of the lever is permitted by deflection of the wire-likespring without appreciably further stressing the leaf spring. The levermay be moved in the opposite direction without actuating the switch.

The present invention relates in general to switches and moreparticularly to limit switches wherein provision is made for overtravelof the actuating member.

Limit switches have been known and used for many purposes in the art andparticularly in the automatic garage door art for example, wherein it isdesired to electrically deactuate an electric motor when the door hasarrived at either an open or closed position. Because of the inertia ofthe mechanism which engages and actuates the switch it is oftennecessary to make provision for overtravel without damage to the switch,i.e. the contacts or member(s) which engage the contacts upon actuation.Many devices of this type have been relatively complicated inconstruction and operation and as a result comparatively expensive tomanufacture.

It is therefore an object of the present invention to provide a limitswitch of the type described which is of an economical construction yetis reliable in operation.

Another object of the present invention is to provide a limit switchwhich provides a simple and reliable construction for overtravel betweenthe movable member and the switch contact or contacts which areactuated.

Another object of the present invention is to provide a limit switchwhich includes contact means actuated through the medium of lever meansfixedly carrying spring means therewith, with another portion of thespring means actuating the contact means upon movement of the levermeans and the spring means permitting further movement of the levermeans after the contact means have been actuated.

Other objects and a fuller understanding of this invention may be had byreferring to the following description and claims, taken in conjunctionwith the accompanying drawings in which:

FIGURE 1 is an elevational view showing the environmnet of two switchesof the present invention as associated with a motor operated garagedoor;

FIGURE 2 is an enlarged elevational view of the limit switch of thepresent invention in actuated condition;

FIGURE 3 is a view taken generally along the line 3-3 of FIGURE 2; and

FIGURE 4 is a view taken generally along the line 4-4 of FIGURE 3showing the switch in unactuated condition.

The limit switch of the present invention is susceptible of many uses,however, in order to illustrate .a preferred embodiment, it has beenillustrated in its use with a motor operated garage door. In thisconnection there has been shown in FIGURE 1 a garage door .15 which isadapted to move on a track 16 between an up position 19 wherein it isgenerally parallel with the ceiling of the Patented Apr. 15, 1969enclosure 17 which it closes, and a down position in which it is shownin the full line position of FIGURE 1. A channel 24 is secured to theceiling of the enclosure and comprises a horizontal guideway 25 withinwhich a carriage 27 is adapted to move back and forth. The channel 24serves to house a worm 29 which is rotatably driven by an electric motorand appropriate gear reduction mechanism contained in housing 30.Driving connection is made between the worm 29 and the carriage 27 t bymeans of a partial nut 32 which meshes with the worm 29 and at anopposite portion (not shown) is connected to the carriage. The carriage27 is pivotally connected to one end of a drive link 18 at 21 and theother end of the link is pivotally connected at 23 to the door 15. As aresult of this construction the door moves between its up and downpositions as the carriage 27 travels back and forth in the guideway 25.

Two of the limit switches of the present invention have been illustratedin FIGURE 1 and have been identified respectively by the referencenumerals 35 and 36. As mentioned, these two limit switches are adaptedto control the up and down movement of the door and in that sensecontrol electrical circuit means which supply power to the motorcontained in housing 30. The electrical circuit means will not befurther described in this application, however, the function performedby switches 35 .and 36 may be the same as that performed by switches 75and 76 respectively in United States Patent No. 2,992,378 issued July11, 1961. In this sense switch 35 may be described as a normally openmomentary contact up travel limit switch and switch 36 as a normallyopen momentary contact down travel limit switch.

Since the details of construction of switches 35 and 36 are identicalonly the specific structure of switch 36 will be described hereinafter.This switch comprises a support member 38 which is fixedly secured tothe channel 24 by means of a screw 39. The switch includes a first fixedcontact 41 which is electrically connected to a conductor 42 by way of aterminal 43 extending from the contact 41. A second movable contact 45is carried on one end of a leaf spring member 47, sometimes referred toas a second spring member, with the other end of the leaf spring memberbeing carried on the support member 38. It is shown as being a groundedswitch. by being secured to the metallic support member 38 by means of arivet 48. The movable contact 45 is therefore connected to ground by wayof the leaf spring member, support member 38 and the channel 24. Theleaf spring member 47 also serves to, in this embodiment, maintain thesecond contact 45 in a first position in which the first and secondcontacts are normally in spaced or open relationship with respect toeach other.

A lever member 50 is provided which has first and second end portionsand a pivot member 52 pivotally connects the first end portion of thelever member to the support tmember 38. This lever member 50 normallyhangs by the action of gravity in the position in which it is shown inFIGURES 3 and 4. A wire-like spring member 54 is provided which hasfirst and second end portions 56 and 57, respectively, and anintermediate portion 58. The first end portion of the wire-like springmember is fixedly connected to the lever member by means of extendingthrough a strap 60 which is formed of the material of the lever memberas shown in the drawings. The intermediate portion of the spring member54 extends or is wound around the pivot member 52 with the second endportion 57 extending to a position immediately adjacent the leaf springmember 47 in the area of the movable contact 45 when the lever member 50is in its inactive position as shown in FIGURE 4.

The carriage 27, sometimes referred to as a movable member, carries aprojection or moving member 62 in the nature of a coil spring which isadapted to engage the lower or second end portion of the lever member 50when it reaches a given position after movement in a first directionshown by arrow 45? When the projection 62 engages the lever member thelever member is adapted to rotate in a counter-clockwise direction asseen in FIGURES 2 and 4 which in turn causes the second end portion 57of the wire-like spring member to engage the leaf spring member 47 andovercome the force thereof to move the movable contact into engagementwith the fixed contact 41 thereby performing the electrical function forwhich it is designed, The door 15 and moving carriage 27 have inertiaand it is necessary to expend this inertia without causing damage to anyof the switch parts. As a result, over-travel of the lever member 50 ispermitted because the wire-like spring member 54 and particularly theintermediate portion 58 thereof simply is resiliently deformed as seenin FIGURE because the closed contacts resist further movement with aforce greater than that of spring member 54, which permit the levermember to move further without causing further movement of the switchcontacts. If the inertia is suificient, the projection 62 may pass tothe right completely beyond engagement with the second end portion ofthe lever member before coming to a complete stop at which time gravitywill cause the lever member to reassume the position shown in FIG- URE4. When the carriage 27 is caused to move to the left so as to bring thedoor to the completely open position, when desired by an operator,movement of the lever member 50 in a clockwise direction is permittedwithout causing further functioning of the switch because of theposition of the lever member and spring member 54 relative to the fixedmovable contacts of the switch. The projection 62 engages the levermember 50 of switch 35 when the door reaches its open position andfunctions in the same manner to cause de-energization of the drivemotor.

It will thus be seen that in accordance with the teachings of thepresent invention a limit switch has been provided that is of aneconomical construction and yet is reliable in operation. Thecombination of the lever and spring means provides a novel overtravelconstruction.

The wire-like spring member 54 may also be considered a first resilientmeans which is movably carried on the support member 38 for actuatingthe contact means 41 and 45 by movement of the moving member 62. Thisfirst resilient means 54 has an actuator arm or first end portion 56, anactuated arm or second end portion 57 and has an overtravel means orintermediate portion 58. This overtravel means is wound and is capableof being stressed as a torsion spring. During actuation of the switch 36by the projection 62 moving in the direction of the arrow 63, theactuator arm 56 is moved counter-clockwise as viewed in the drawing andthis first closes the contacts 41 and 45 by stressing and overcoming theresistance of the second resilient means or leaf spring member 47. Afterthe contacts 41 and 45 are closed then the contact 45 is in the secondposition and this resists further movement of the leaf spring member 47.Accordingly for further movements of the moving member 62 in thedirection of the arrow 63, the first resilient means 54 is merelystressed further to permit movement of the first end portion 56 and thelever member 50. This overtravel stresses the intermediate portion 58 asa torsion spring to readily permit such overtravel without harm to theswitch mechanism 36 and without material further movement of this leafspring member 47.

Although this invention has been described in its pre ferred form with acertain degree of particularly, it is understood that the presentdisclosure of the preferred form has been made only by Way of exampleand that numerous changes in the details of construction and thecombination and arrangement of parts may be resorted to withoutdeparting from the spirit and the scope of the invention as hereinafterclaimed.

What is claimed is:

1. A limit switch including in combination, a support member,

fixed contact means,

movable contact means cooperable with said fixed contact means,

a leaf spring member having first and second end portions,

means fixedly connecting said first end portion of said leaf springmember to said support member,

said movable contact means being mounted on said second end portion ofsaid leaf spring member,

a flat lever member having first and second end portions,

pivot means pivotally connecting said first end portion of said levermember to said support member with said flat lever member having a widthdimension parallel to said support member at the pivot means to beguided in pivotal movement by said support member,

a wire-like spring member having first and second end portions and anintermediate portion,

said first end portion of said wire-like spring member being fixedlyconnected to said lever member and said intermediate portion extendingaround said pivot means with said second end portion extending to aposition adjacent said second end portion of said leaf spring member,

said second end portion of said lever member adapted to be engaged by amoving member moving in a first direction and when so engaged pivotallymoving said lever member about said pivot means and angularly movingsaid second end portion of said Wire-like spring member into engagementwith said leaf spring member to move said contact means relative to eachother anad said wire-like spring member deflecting to permit continuedovertravel movement of said lever member relative to said contact meansafter said contact means have been moved relative to each other.

2. A switch as claimed in claim 1, wherein said second end portion ofsaid lever member is arranged to be moved in a second direction oppositeto said first direction to move said wire-like spring member away fromsaid leaf spring member for non-actuation of said contact means.

3. A switch as claimed in claim 1, wherein said pivot means pivotallyinterconnects said support member and said lever member at only onelocation with said lever member guided in movement by said supportmember.

References Cited UNITED STATES PATENTS 2,511,271 6/1950 Kaminky et al.2,939,337 6/1960 Sweger.

ROBERT K. SCHAEFER, Primary Examiner.

D. SMITH, JR., Assistant Examiner.

US. Cl. X.R. 200153

